КООРДИНАЦИОННОЕ СВЯЗЫВАНИЕ В СИНТЕЗЕ ЗАМЕЩЁННЫХ ПОЛИОКСИЭТИЛЕНГЛИКОЛЕМ ЧАСТИЦ КРЕМНЕЗЁМА

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One of the main methods for producing modified silica particles is based on sol-gel synthesis processes traditionally used to produce silica gels, xerogels and aerogels. this method includes the stage of hydrolysis of alkoxysilanes with the formation of a sol (colloidal system), followed by the process of condensation of silanol groups and conversion of the sol to a gel. due to the high probability of the formation of cross-linked topological structures during sol-gel processes, it is challenging to use this method to obtain unrelated individual organo-substituted silica particles (ASiP). In this regard, the solution to the problem of producing ASiP and si ng alkoxysilanes as a central reagent is based on the selection of suitable catalysts. alkoxysilanes usually react slowly with water, but the reaction process can be accelerated using acidic or basic catalysts. for example, the gelation time of tetraethoxysilane (TEOS) can increase a hundredfold when using HCl. The use of an alkaline catalyst, on the contrary, leads to a noticeable decrease in the rate of TEOS hydrolysis. In this work, CuCl2was used to carry out the gel-sol process involving polyoxyethylene glycol (PEG) and TEOS and synthesize branch-substituted PEG Silicas (ASiP-Cu). A comparative study of the particle size distribution of PEG and ASiP-Cu was carried out. An increase in the CuCl2 content during the production of silicas substituted with polyoxyethylene branches from 0.01 wt.% to 0.5 wt.% leads to a decrease in the Size of the resulting particles, reaching a minimum value of 200 nm at 0.5 wt.% CuCl2. Analysis of the results of measuring the size of ASiP-Cu particles and electronic spectra allows us to conclude that CuCl2 at 0.01 wt.% catalyzes the gel-sol process leading to the formation of ASiP-Cu, but at such a low content copper chloride does not enter into complex-forming interactions with polyoxyethylene glycol, which is an integral part of the ASiP-Cu structure. An increase in the copper chloride content to 0.1 wt.% entails a significant change in the structural organization of ASiP-Cu. In this case, copper chloride coordinately binds to open-chain crown ether analogues by trapping Cu(II) ions into the crown cavity created by the polyoxyethylene glycol branches of the ASiP-Cu particles.